Dishmachines have to effectively clean a variety of articles such as pots and pans, glasses, plates, bowls, and utensils. These articles include a variety of soils including protein, fat, starch and sugar, which can be difficult to remove. At times, these soils may be burnt or baked on, or otherwise thermally degraded. Other times, the soil may have been allowed to remain on the surface for a period of time, making it more difficult to remove. Dishmachines remove soil by using a combination of detergents, temperatures, sanitizers or mechanical action from water.
Often enzymes are employed to assist in soil removal. Enzymes present an alternative to aggressive chemistries for cleaning a variety of articles and difficult to remove soils. Often enzymes are employed to replace a surfactant to enhance soil removal and provide a more sustainable detergent composition, such as those that are phosphate-free. But, a challenge to enzymes is maintaining their stability in solution in the presence of water or incompatible chemistries. In order to market an aqueous enzyme composition, the enzyme must be stabilized so that it will retain its functional activity for prolonged periods of time (e.g. shelf-life or storage). Enzymes are generally unstable in solution without a stabilizing system and therefore require excess amounts of enzymes to compensate for the expected loss. This is undesirable due to the high cost of enzymes.
Enzyme instability in solution may result from incompatible chemistry (e.g. surfactants and antimicrobials) denaturing the enzyme, or autolysis in the presence of protease where the protease attacks other enzymes. Enzyme stabilization systems exist but have drawbacks. For example, boric acid or borate stabilization systems are restricted in certain countries. It is against this background that this invention is made.
Accordingly, it is an objective of the invention to develop improved enzyme compositions for use in soil removal in dishmachines.
A further object of the invention is to provide liquid stable enzyme compositions for warewashing, dishwashing and other cleaning applications requiring the use of enzymes, namely synergistic combinations of enzymes for a particular cleaning application, regardless of whether one or more of the enzymes are stabilized using an alternative mechanism (e.g. stabilized protease enzymes).